MQTT

MQTT support for the FANUC R-50iA and R-30iB Plus controllers enables robot controllers to exchange data with external systems using a publish-subscribe communication model. With the MQTT option, the robot can connect to an MQTT broker as a client and operate as a publisher, subscriber, or both. This allows robot data, application messages, status information, or custom KAREL-generated payloads to be sent to and received from connected systems without requiring direct point-to-point polling. The controller supports MQTT version 5.0 and includes FANUC KAREL built-in routines for connecting, publishing, subscribing, receiving published messages, unsubscribing, and disconnecting from the broker. 

The MQTT function is designed for flexible automation integration. Robot applications can publish messages to defined topics with QoS 0, QoS 1, or QoS 2, allowing the application to choose the right delivery assurance for the use case. The controller can also subscribe to topics and retrieve incoming payloads through KAREL pipe files, making it possible to pass instructions, configuration values, event messages, or other application-specific data into robot logic. Messages are handled through KAREL routines such as MQTT_PUBLISH, MQTT_SUBSCRIBE, and MQTT_GET_PUBLISH, giving developers direct programmatic control over MQTT communication from the robot controller.

For secured deployments, MQTT TLS Client support adds encrypted communication between the robot controller and the MQTT broker. MQTT TLS requires both the MQTT option and the MQTT TLS Client option, supports TLS 1.2, and uses trusted CA certificates imported into the controller. Extended connection settings allow the KAREL program to define username, password, TLS usage, and broker port through a settings pipe file. This supports authenticated broker connections and helps protect MQTT traffic in production network environments. 

The MQTT implementation supports the most common client operations needed for industrial data exchange, including CONNECT, PUBLISH, SUBSCRIBE, UNSUBSCRIBE, and DISCONNECT. The controller cannot act as an MQTT broker, which keeps the feature focused on client-side robot communication with an external broker or cloud-connected middleware. MQTT TLS supports one TLS connection at a time, and ROBOGUIDE supports MQTT but does not support MQTT TLS.

This feature is well suited for applications that need lightweight, event-based communication between robots, edge devices, MES systems, dashboards, and cloud gateways. By using topics and publish-subscribe messaging, robot data can be shared with multiple systems through a broker while keeping the robot application clean and structured. For facilities building modern IIoT architectures, MQTT provides a practical way to connect robot-level information to broader digital manufacturing systems.